Investigation of microstructure and impact toughness of semisolid hypereutectic high chromium cast iron prepared by slope cooling body method

In this study, Semisolid hypereutectic high Cr cast iron specimen was obtained by slope cooling body method under the condition of different technics parameters (different pouring temperatures and slope angles). By microstructures analysis and impact toughness test of semisolid specimens, the results indicate that, firstly, the primary carbides in the semisolid microstructure are finer than those in the hypereutectic high Cr cast iron prepared by conventional method; secondly, with a decrease in the semisolid forming temperature, the primary carbides become fine; thirdly, the optimal impact toughness value of the semisolid specimen increases above one times more than that of hypereutectic one prepared by conventional method. The results also indicate that, there are lots of shrinkage porosities in the semisolid microstructure, furthermore, with a decrease in the semisolid forming temperature, the tendency of shrinkage porosities become obvious. Thus, in the next work, it would be significant for improving the impact toughness of semisolid hypereutectic high Cr one to eliminate shrinkage porosities by extrusion forming or other methods.